The invention relates to indicating and control apparatus for appliances and, more particularly, to such apparatus which provides automatic shut-off and audible and visible indicating signals.
In appliances including variable-temperature heaters, it is desirable to include features which provide increased safety and convenience to the user. For example, it is known in the art to provide appliances including variable-temperature heaters having automatic shut-off devices. Furthermore, it is known in the art to provide appliances which include various audible and visible indications to the user of the temperature status of the appliance. However, prior art implementations of these features sometimes yielded inconsistent indicating signals which confused the user and resulted in shut-off of the appliance in an annoying and inconvenient manner. Moreover, when the user selected a different desired temperature, inaccurate "ready" indications would sometimes occur. Thus, the prior art has failed to provide such features in a manner which yielded the required degree of safety and operating convenience. It is therefore desirable to provide an appliance having a variable temperature heater which will provide to the user a simple positive audible and visible "ready" signal indicating that the temperature of the appliance renders the appliance suitable for use and wherein a "ready" indication will be provided following a change in desired temperature only when the associated appliance reaches the newly selected temperature. It is further desirable to provide an appliance including the safety feature of an automatic shut-off after a predetermined period of nonuse, with the shut-off feature preceded by a signal indicating that shut-off is about to occur.